Posessing the qualities of ridiculous-beyond-belifedness for an extended period of time in multiple ways.

Refers to the words Bullshit (meaning a possible lie or deception, usually to the point of being unbelieveably ridiculous) and Fest (meaning a gathering of a kind, a celebration, usually lasting a decent amount of time).

BP's reasons for not

The online Psych 101 Labs that Dr. Gremble assigned are a total Bullshitfest. They take forever... and they have nothing to do with the human mind!

My Ex-Girlfriends excuses like "Washing my hair" always smelled of a total Bullshitfest.